T cell responses to highly active antiretroviral therapy defined by chemokine receptors expression, cytokine production, T cell receptor repertoire and anti-HIV T-lymphocyte activity

Editorial to the Special Issue "Clinical Immunology in Italy, with Special Emphasis to Primary and Acquired Immunodeficiencies: A Commemorative Issue in Honor of Prof. Fernando Aiuti"

Fernando Aiuti (Figure 1), born in Urbino on 8 June 1935, suddenly died on 9 January 2019, leaving a great void not only among his family members and those who knew him and appreciated his great humanity and acute intelligence, but in the entire immunological scientific community [...].

Enhancement of Cluster Differentiation Antigen 4 and the Body Mass Index in Patients with HIV

<b>Background and Objective:</b> The HIV is the virus that can cause AIDS by attacking white blood cells such as T cells CD4<sup>+</sup>. This study aimed to determine the relationship between antiretroviral (ARV) drugs and supplements of black tea (<i>Camellia sinensis</i> var. <i>assamica</i>) powder to increase the CD4 and Body Mass Index (BMI) in patients with HIV. <b>Materials and Methods:</b> This study used a quasi-experiment. From the average number of 10 patient visits every month in the period of January to March, 2021 in the outpatient clinic for patients diagnosed positive with HIV-AIDS, seventy patients were enlisted and divided into 2 groups from 12 districts, 35 groups intervention received ARV drugs and supplements steeping black tea powder form as much as 1,505 mg, equivalent to 5-7 glasses a 1,000-1,400 mL/day for 24 weeks, while the control group of patients received ARV drugs, standard diet each house and nutrition education. <b>Results:</b> This study showed a BMI before the intervention control group's 1st week 19.31±2.17 and after the intervention for 24 weeks, a BMI of 18.78±2.42. CD4 levels before the intervention, the 1st week were 380.57±78.63 and after the intervention for 24 weeks, 365.74±81.13 in this case either BMI or CD4 did not experience significant improvements. While the intervention group before the intervention 1st week BMI was 21.61±3.32 and after the intervention for 24 weeks, 22.2±3.19 or increased significantly (p = 0.002) and the levels of CD4 in the 1st week before the intervention, 360.91±221.20 and after the intervention for 24 weeks, 425.14±178.87 or increased significantly (p = 0.003). <b>Conclusion:</b> The ARV therapy and black tea powder significantly increased levels of CD4 and BMI HIV sufferers through the improvement of the status of T-cell immunity and body mass index.

Frequency of Effector Memory Cells Expressing Integrin α4β7 Is Associated With TGF-β1 Levels in Therapy Naïve HIV Infected Women With Low CD4+ T Cell Count

Integrin α₄β₇ expressing CD4⁺ T cells are preferred targets for HIV infection and are thought to be predictors of disease progression. Concurrent analysis of integrin α₄β₇ expressing innate and adaptive immune cells was carried out in antiretroviral (ART) therapy naïve HIV infected women in order to determine its contribution to HIV induced immune dysfunction. Our results demonstrate a HIV infection associated decrease in the frequency of integrin α₄β₇ expressing endocervical T cells along with an increase in the frequency of integrin α₄β₇ expressing peripheral monocytes and central memory CD4⁺ T cells, which are considered to be viral reservoirs. We report for the first time an increase in levels of soluble MAdCAM-1 (sMAdCAM-1) in HIV infected individuals as well as an increased frequency and count of integrin β7Hi CD8⁺ memory T cells. Correlation analysis indicates that the frequency of effector memory CD8⁺ T cells expressing integrin α₄β₇ is associated with levels of both sMAdCAM-1 and TGF-β1. The results of this study also suggest HIV induced alterations in T cell homeostasis to be on account of disparate actions of sMAdCAM-1 and TGF-β1 on integrin α₄β₇ expressing T cells. The immune correlates identified in this study warrant further investigation to determine their utility in monitoring disease progression.

Harnessing CD8+ T Cells Under HIV Antiretroviral Therapy

Antiretroviral therapy (ART) has transformed HIV from a fatal disease to a chronic condition. In recent years there has been considerable interest in strategies to enable HIV-infected individuals to cease ART without viral rebound, either by purging all cells infected harboring replication-competent virus (HIV eradication), or by boosting immune responses to allow durable suppression of virus without rebound (HIV remission). Both of these approaches may need to harness HIV-specific CD8⁺ T cells to eliminate infected cells and/or prevent viral spread. In untreated infection, both HIV-specific and total CD8⁺ T cells are dysfunctional. Here, we review our current understanding of both global and HIV-specific CD8⁺ T cell immunity in HIV-infected individuals with durably suppressed viral load under ART, and its implications for HIV cure, eradication or remission. Overall, the literature indicates significant normalization of global T cell parameters, including CD4/8 ratio, activation status, and telomere length. Global characteristics of CD8⁺ T cells from HIV⁺ART⁺ individuals align more closely with those of HIV-seronegative individuals than of viremic HIV-infected individuals. However, markers of senescence remain elevated, leading to the hypothesis that immune aging is accelerated in HIV-infected individuals on ART. This phenomenon could have implications for attempts to prime de novo, or boost existing HIV-specific CD8⁺ T cell responses. A major challenge for both HIV cure and remission strategies is to elicit HIV-specific CD8⁺ T cell responses superior to that elicited by natural infection in terms of response kinetics, magnitude, breadth, viral suppressive capacity, and tissue localization. Addressing these issues will be critical to the success of HIV cure and remission attempts.

Identification of Native and Posttranslationally Modified HLA-B*57:01-Restricted HIV Envelope Derived Epitopes Using Immunoproteomics

The recognition of pathogen-derived peptides by T lymphocytes is the cornerstone of adaptive immunity, whereby intracellular antigens are degraded in the cytosol and short peptides assemble with class I human leukocyte antigen (HLA) molecules in the ER. These peptide-HLA complexes egress to the cell surface and are scrutinized by cytotoxic CD8+ T-cells leading to the eradication of the infected cell. Here, naturally presented HLA-B*57:01 bound peptides derived from the envelope protein of the human immunodeficiency virus (HIVenv) are identified. HIVenv peptides are present at a very small percentage of the overall HLA-B*57:01 peptidome (<0.1%) and both native and posttranslationally modified forms of two distinct HIV peptides are identified. Notably, a peptide bearing a natively encoded C-terminal tryptophan residue is also present in a modified form containing a kynurenine residue. Kynurenine is a major product of tryptophan catabolism and is abundant during inflammation and infection. Binding of these peptides at a molecular level and their immunogenicity in preliminary functional studies are examined. Modest immune responses are observed to the modified HIVenv peptide, highlighting a potential role for kynurenine-modified peptides in the immune response to HIV and other viral infections.

Targeting Tuberculosis and HIV Infection-Specific Regulatory T Cells with MEK/ERK Signaling Pathway Inhibitors

Human regulatory T cells (Tregs) are essential in maintaining immunological tolerance and suppress effector T cells. Tregs are commonly up-regulated in chronic infectious diseases such as tuberculosis (TB) and human immunodeficiency virus (HIV) infection and thereby hamper disease-specific immune responses and eradication of pathogens. The MEK/ERK signaling pathway is involved in regulation of the FoxP3 transcription factor, which directs a lineage-specific transcriptional program to define Tregs and control their suppressive function. Here, we aimed to target activation of disease-specific Tregs by inhibition of the MEK/ERK signaling pathway based on the hypothesis that this would improve anti-HIV and anti-TB immunity. Stimulation of T cells from untreated TB (n = 12) and HIV (n = 8) patients with disease-specific antigens in vitro in the presence of the MEK inhibitor (MEKI) trametinib (GSK1120212) resulted in significant down-regulation of both FoxP3 levels (MFI) and fractions of resting (CD45RA⁺FoxP3⁺) and activated (CD45RA⁻FoxP3⁺⁺) Tregs. MEKI also reduced the levels of specific T effector cells expressing the pro-inflammatory cytokines (IFN-γ, TNF-α and IL-2) in both HIV and TB patients. In conclusion, MEKIs modulate disease antigen-specific Treg activation and may have potential application in new treatment strategies in chronic infectious diseases where reduction of Treg activity would be favorable. Whether MEKIs can be used in current HIV or TB therapy regimens needs to be further investigated.

Preserving HIV-specific T cell responses: does timing of antiretroviral therapy help?

PURPOSE OF REVIEW

HIV-specific T cell responses are likely to have an important role in HIV cure strategies that aim for long-lasting viral control without antiretroviral therapy (ART). An important issue in enhancing virus-specific T cell responses is whether timing of ART can influence their magnitude and breadth.

RECENT FINDINGS

Early ART is associated with lower T cell activation, preservation of T cell numbers, smaller DNA and RNA reservoir size, and, in a single study (VISCONTI), control of plasma viremia after treatment interruption. The prevention of T cell destruction by early ART is associated with relatively low anti-HIV CD8⁺ T cell responses but stronger CD4⁺ T helper function. The relatively lower CD8⁺T cell response, which is presumably due to rapid lowering of HIV antigen burden after early ART, appears sufficient to control residual viral replication as well as viral rebound upon treatment interruption.

SUMMARY

Available evidence of starting ART during acute or early HIV infection has shown benefit in both virologic and immunologic parameters despite the lower HIV-specific CD8⁺ T cell responses observed. Encouraging as this is, more extensive data are necessary to evaluate its role in combination with immunotherapeutic and latency activation strategies that are being assessed in various HIV cure-related studies.

The number of CCR5 expressing CD4+ T lymphocytes is lower in HIV-infected long-term non-progressors with viral control compared to normal progressors: a cross-sectional study

Background

The HIV co-receptors CXCR4 and CCR5 play an important role in HIV infection and replication. Therefore we hypothesize that long-term non-progressors (LTNP) with viral control have lower expression of CCR5 and CXCR4 on CD4⁺ cells, specifically on memory T-lymphocytes since they are the primary target cells of HIV.

Methods

In this cross-sectional study, we included five HIV-infected LTNP with viral control (CD4 > 750 cell/μl & HIV < 50 copies for ≥2 years), thirteen HIV-infected and seven HIV-uninfected individuals at Radboud UMC Nijmegen, the Netherlands. We determined the CCR5 and CXCR4 expression among CD4⁺ and CD8⁺ lymphocyte subsets; memory (CD45RO⁺), naïve (CD45RA⁺) cells and regulatory T-cells (CD4⁺CD25^highFoxP3⁺). In addition, CCR5∆32 polymorphism is related with disease progression and was therefore determined using polymerase chain reaction.

Results

The percentage of CCR5-expressing CD4⁺ cells of LTNP was comparable with healthy controls; whereas HIV-infected individuals showed more CCR5-expressing cells. This was observed in memory and naïve CD4⁺ cells, but not in regulatory T-cells. The mean fluorescence intensity of CCR5-expressing CD4⁺ cells was similar in all groups. All groups had comparable percentages of CXCR4-expressing cells. The mean fluorescence intensity of CXCR4-expressing cells was significantly higher in HIV-infected normally progressors in both memory and naïve CD4⁺ cells, but not in CD8⁺ cells. The CCR5∆32 polymorphism was not related to group.

Conclusions

We show that HIV affects -directly or indirectly- the expression of CCR5 in CD4⁺ T-lymphocytes; yet this effect is not seen in LTNP with viral control. Avoiding upregulation of CCR5 could be an important method via which LTNP counteracts the effects of HIV and suppresses viral replication. Exploring how LTNP suppress the upregulation of CCR5 could be an important step for discovering new therapeutics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0683-0) contains supplementary material, which is available to authorized users.

CD8 TCR β chain repertoire expansions and deletions are related with immunologic markers in HIV-1-infected patients during treatment interruption

BACKGROUND

HIV-1-infected individuals progressively loss CD4(+) T cells leading to immunosuppression and raising the risk of opportunistic infections. CD8(+) T-cells play an important role in the immune response against virus infections through their TCR.

OBJECTIVE

To evaluate the CD8-TCR repertoire and immunologic markers in HIV-1-infected patients.

STUDY DESIGN

Ten chronic HIV-1-infected individuals on prolonged effective antiretroviral treatment (ART) were analyzed at baseline (before treatment interruption), after at least one year of treatment interruption (TI) and after at least one year from ART resume (TR). Twenty-four TCR-Vβ gene families were analyzed by a modified CDR3 spectratyping method in isolated CD8(+) T-cells. Immune activation, exhaustion and subpopulation markers were analyzed by flow cytometry.

RESULTS

Expansion of Vβ10, Vβ14 and Vβ15 families, associated with low cell activation and stable exhaustion markers, were found at TI. Moreover, an increment of effector memory cells was found. Besides, depletion of Vβ20, Vβ28, and Vβ29 families, associated with an increase in cell activation and exhaustion markers, at TI were also found. These alterations seemed to be more pronounced in patients who had longer time from diagnosis. ART seemed to restore altered CD8(+) T-cell repertoire and most of the immunologic markers.

CONCLUSIONS

During TI (that was more pronounced in patients with longer HIV-1 infection) it was observed the expansion of Vβ families correlated with decreased cell activation, while Vβ families correlated with cell activation and exhaustion were depleted. These specific repertoire alterations reverted after ART resume.

Altered clonogenic capability and stromal cell function characterize bone marrow of HIV-infected subjects with low CD4+ T cell counts despite viral suppression during HAART

BACKGROUND

Inflammatory cytokines in bone marrow may impair hematolymphopoiesis in human immunodeficiency virus (HIV)-infected subjects who do not experience reconstitution of CD4(+) T cells despite suppression of virus replication while receiving highly active antiretroviral therapy (HAART) (immunological nonresponders).

METHODS

Bone marrow samples from 12 immunological nonresponders receiving HAART were studied and compared with samples from 11 immunological responders. The mean CD4(+) T cell count (+/- standard deviation) was 174 +/- 68 cells/mm(3) and plasma HIV RNA levels had been <50 copies/mL for at least 1 year for individuals enrolled in the study. The clonogenic capability of bone marrow samples was evaluated using the colony forming cell assay and the long-term culture-initiating cell assay. CD34(+) cells from the colony forming cell assay were pooled for real-time polymerase chain reaction analysis of Fas and Fas ligand. Bone marrow cytokine production (interleukin-2 and tumor necrosis factor-alpha) and stromal interleukin-7 levels were analyzed by enzyme-linked immunosorbent assay in both groups. Flow cytometric analysis of CD4(+) and CD8(+) T cell subsets was performed.

RESULTS

A reduced clonogenic capability and a decrease in the level of more primitive progenitor cells were observed in parallel with lower production of interleukin-2 and increased tumor necrosis factor-alpha levels. A significant upregulation of Fas and Fas ligand on CD34(+) cells and a higher stromal interleukin-7 production were observed. Impairment of the naive T cell compartment and persistent T cell activation were observed in peripheral blood.

CONCLUSIONS

Samples from immunological nonresponders show reduced growth of in vitro colonies and an altered cytokine production in bone marrow. The cytokine pattern observed and the altered Fas and Fas ligand pathway may determine stem cell apoptosis and low CD4(+) cell recovery. These features, which are similar to those observed in HIV-infected subjects before starting therapy, persist despite treatment.

Factors impacting the expression of membrane-bound proteins in lymphocytes from HIV-positive subjects

BACKGROUND

The cellular transport proteins ABCB1, ABCC1 and ABCG2 have been implicated in the efflux of some antiretroviral drugs, thus decreasing their intracellular concentrations. Decreased drug accumulation in lymphocytes may allow viral replication and the subsequent emergence of viral resistance leading to treatment failure. Expression of HIV co-receptors on the surface of lymphocytes may influence viral tropism and therefore viral pathogenicity and disease progression. Here, we describe the relationship between expression of transport proteins and chemokine receptors in lymphocytes isolated from HIV-infected individuals and also investigate their relationship with demographic, therapeutic and virological factors.

METHODS

Peripheral blood mononuclear cells (PBMC) isolated from HIV-positive individuals were co-stained for expression of CD4 and ABCB1, ABCC1, ABCG2, CXCR4 and CCR5. The influence of gender, ethnicity, treatment status, viral load and CD4 count was assessed on expression of each protein as well as correlations between expression of the proteins by univariate and multivariate analyses.

RESULTS

Expression of ABCB1 was independently associated with gender (n = 98) and expression of ABCG2 and CXCR4. Gender also correlated with expression of ABCC1 and CXCR4 in univariate analysis with lower expression being detected in females compared with males.

CONCLUSIONS

Here we confirm that the previously reported correlation between ABCB1 and CXCR4 observed in PBMC isolated from healthy volunteers is also found in HIV-positive individuals. The influence of gender on the expression of drug efflux proteins could be a determinant of intracellular drug concentrations in vivo.

Short communication: decreasing soluble CD30 and increasing IFN-gamma plasma levels are indicators of effective highly active antiretroviral therapy

It was previously reported that without highly active antiretroviral therapy (HAART), secretion of Th1 cytokines and antiviral IFN-gamma in HIV-infected patients is decreased, whereas the production of Th2 cytokines, proinflammatory cytokines, and TNF-alpha is increased. We studied the effect of HAART on Th1-, Th2-, and monocyte-derived cytokines, and on the Th2-type immune response marker soluble (s)CD30 in HIV-1-infected hemophilia patients. Viral Load (VL), CD4+ lymphocyte counts, and plasma levels of sIL-1RA, IL-2, sIL-2R, IL-3, IL-4, IL-6, sIL-6R, IL-7, IL-10, TNF-alpha, TGF-beta2, IFN-gamma, and sCD30 were measured in 18 patients who received HAART. Nine patients were initially treatment-naive and were monitored after the initiation of HAART. sCD30 median levels were significantly higher in treatment-naive patients than in patients who were on HAART (77 vs. 30 U/ml, p = 0.005). A strong association was observed between sCD30 and VL (r = 0.85, p = 0.004). After the initiation of HAART, sCD30 levels decreased and remained low (at 1 year, 38; at 2 years, 41 U/ml; p = 0.012 and p = 0.021, respectively, as compared to baseline level) and this was accompanied by a decrease in VL and monocyte-derived IL-6 and an increase in CD4+ lymphocyte counts and Th1-derived IFN-gamma. One year after the initiation of HAART a strong inverse correlation was observed between IFN-gamma and VL (r = -0.83, p = 0.006). In contrast to sCD30 and IFN-gamma, CD4 counts and plasma IL-6 did not correlate with VL at any time. Our data suggest that decreasing sCD30 and increasing IFN-gamma plasma levels are indicators of effective HAART treatment and CD4 Th1 cell recovery in HIV-infected patients.

Does cyclosporin A affect CCR5 and CXCR4 expression in primary HIV-1-infected patients?

BACKGROUND

CCR5 and CXCR4 are the major coreceptors of HIV required for successful viral entry. No information exists on the effect of cyclosporin A (CsA) on expression of CCR5 and CXCR4. A longitudinal study of the coreceptors' expression in freshly isolated peripheral blood mononuclear cells (PBMC) of patients with primary HIV infection (PHI) was performed.

METHODS

Patients received highly active antiretroviral therapy (HAART) alone (n = 7) or with CsA (HAART + CsA) (n = 8). Flow cytometric data were analyzed at T0 (baseline), two (T2), six (T6), and twelve (T12) months after therapy initiation.

RESULTS

At T0 PHI subjects presented a statistically significant higher count and percentage of CD8+CCR5+ lymphocytes compared to healthy donors (HD) (mean +/- SD, 2,240 +/- 1,998 vs 181 +/- 89 cells/microl). Conversely, CD4+CXCR4+ lymphocytes were less abundant in PHI than in HD (443 +/- 337 vs 673 +/- 339 cells/microl), whereas CD4+CCR5+ lymphocytes were substantially comparable (169 +/- 167 vs 126 +/- 60 cells/microl). In the follow up no differences between HAART and HAART + CsA groups reached statistical significance in CD4 lymphocytes. CD4+CCR5- lymphocytes displayed a rapid recovery after therapy initiation, similarly to the CD4+CXCR4+ subset. In CD8 lymphocytes a statistically significant difference between HAART and HAART + CsA patients occurred at T2 when HAART + CsA patients presented a lower absolute count of the CD8+CXCR4+ subset compared to the HAART group. The major change after therapy initiation in all PHI patients was a striking drop of CD8+CCR5+ lymphocytes; moreover, the CD8+CXCR4- subset behaved similarly. The decrement of CD8+CCR5+ lymphocytes paralleled the decline of viremia and CD8+CD38+ lymphocytes, with the sharpest slope at T2. Conversely, RANTES levels increased at T2 and remained elevated during the follow up.

CONCLUSIONS

CsA cotreatment in PHI patients appears not to substantially modify HIV coreceptors' expression in PBMC. However, this novel piece of information should be used with caution, since this was not a randomized study between the HAART and the HAART + CsA groups.

CD8+ cell noncytotoxic anti-HIV response: restoration by HAART in the late stage of infection

Highly active antiretroviral therapy (HAART) is currently the best HIV infection management strategy. However, its effects on the CD8+ T cell noncytotoxic anti-HIV response (CNAR) are not well known. We investigated if HAART has different effects on CNAR in patients at the intermediate and late stages of HIV infection. Untreated healthy HIV-infected subjects with a mean CD4+ T cell count of 606 cells/microl were examined as a reference group. Plasma viral load, CD4+ T cell count, and CNAR activity were measured at baseline and regular intervals for at least 48 weeks following initiation of HAART. Baseline CNAR activity in all subjects correlated inversely with viral load and directly with CD4 T+ cell counts. The level of CNAR in the latestage group was significantly lower than in the intermediate-stage and the healthy reference group (p < 0.01). Following initiation of HAART, substantial increases in CD4+ T cell counts and decreases in viral loads were observed in both groups, indicating treatment success. CNAR activity was found to be increased significantly during HAART, but only in the late-stage group (p < 0.01). This increase in CD8+ cell function was seen within 4 weeks of treatment initiation and resulted in levels of CNAR activity almost equal to those observed in the healthy reference subjects. Our findings suggest a beneficial effect on CNAR in those individuals with reduced activity, typically in late-stage infection.

Hormonal contraceptive use and the effectiveness of highly active antiretroviral therapy

The role of hormonal contraceptive use in the effectiveness of highly active antiretroviral therapy (HAART) was examined among participants in the Women's Interagency HIV Study who were followed from HAART initiation to 2001. Propensity score selection was used to match 77 hormonal contraceptive users with 77 nonusers on age, race, and pre-HAART CD4-positive T-lymphocyte (CD4+ cell) count and viral load. The authors compared hormonal contraceptive users and nonusers with regard to the CD4+ cell count and viral load responses to HAART upon initiation. Proportional hazards analyses were used to assess the effect of hormonal contraceptive use on times to increases in CD4+ cell count of 50 cells/mm(3) and 100 cells/mm(3) and achievement of an undetectable viral load. There were no statistically significant differences in CD4+ cell counts and log viral load responses by hormone use after HAART initiation, except in log viral load at the third visit after initiation (p = 0.047). Time-dependent hormonal contraceptive use was not a statistically significant predictor of achieving increases in CD4+ cell count of 50 cells/mm(3) and 100 cells/mm(3) or an undetectable viral load (p = 0.517, p = 0.751, and p = 0.218, respectively) after HAART initiation. In conclusion, the authors did not find substantial evidence that use of hormonal contraceptives strongly affected responses to HAART.

HIV type 1 protease inhibitors enhance bone marrow progenitor cell activity in normal subjects and in HIV type 1-infected patients

HIV-1 protease inhibitors (PIs) may improve hematopoietic functions owing to their direct effects on bone marrow (BM) progenitor cells. In this study we investigated this hypothesis evaluating the effect of adding ritonavir (RTV) and indinavir (IND) on hematopoietic colony formation assays by colony-forming cell (CFC) and long-term culture-initiating cell (LTC-IC) assays, on apoptosis, on cytokine production and stromal cells, in subjects with HIV-1 infection, and in seronegative controls. After PI addition, CFC and LTC-IC assays in HIV-1-infected patients showed levels of colony growth significantly higher than those observed at baseline; the same PI activity on colony formation was observed in healthy subjects. No significant modifications on Fas, the membrane form of Fas (mFas) and Fas-ligand (FasL) expression, and on cytokine production were observed at BM level after the addition of PIs. At baseline, in HIV-1-infected patients, the majority of the stromal cells appeared as large and rounded, whereas after the addition of RTV or IND the stromal cells exhibited a "fibroblast-like" morphology and produced higher stem cell factor (SCF) and lower MIP-1alpha levels when compared with the stromal production without the addition of IND. RTV and IND increased colony growth of BM obtained either from HIV-1-infected patients or from normal individuals, in parallel with the normalization of functional and morphological characteristics of stromal cells.

Highly Active Antiretroviral Therapy Restores CD4+ V?? T-Cell Repertoire in Patients With Primary Acute HIV Infection But Not in Treatment-Naive HIV+ Patients With Severe Chronic Infection

In drug-naive HIV+ patients, we analyzed the effects of highly active antiretroviral therapy (HAART) on the reconstitution of the T-cell receptor (TCR) repertoire. We followed 2 groups of patients for 1 year: 18 individuals who experienced acute HIV infection and 24 patients who had HIV infection for many years but never took HAART. They were compared with 10 healthy controls who were longitudinally analyzed for the same period. We performed cytofluorometric analysis of the Vbeta TCR repertoire and detected the clonality of different Vbeta families by the spectratyping method. A new statistical approach based on the use of mixed models was then employed to analyze the data. Before the beginning of therapy, the repertoire of patients with acute or chronic infection was significantly different from that of healthy controls. After therapy, patients with acute HIV infection showed an improvement of the repertoire among either CD4+ or CD8+ T lymphocytes. Conversely, patients with chronic infection were capable of changing their repertoire among CD8+ but not CD4+ T lymphocytes. Our results indicate that HAART can restore the T-cell repertoire in individuals whose immune system is not severely compromised by the infection.

Dissociation of CD4+ cell counts from viral load and association with immune complexes in HIV+ hemophilia patients

OBJECTIVE

We have postulated that the host autoimmune response regulates and mediates CD4 depletion during HIV infection by opsonization of circulating CD4(+) lymphocytes carrying autoreactive immune complexes (IC) consisting of complement-fixing IgM and IgG, and during advanced stages of HIV disease of IgM/ IgG/gp120 complexes. In this retrospective study, we investigated whether HIV causes CD4 depletion by direct cytotoxicity or indirectly by induction of a host autoimmune response.

PATIENTS AND METHODS

In 1996, 12 HIV(+) hemophilia patients were converted to highly active antiretroviral therapy (HAART), while 10 other patients were maintained on conventional antiretroviral treatment and another 11 patients refused to be treated with antiretroviral drugs. The host immune response of these 33 HIV(+) patients was studied during the periods of minimum viral replication (Interval 1), subsequent rise in viral replication with strong replication dynamic (Interval 2), and maximum viral replication (Interval 3). The patients were categorized into three groups according to viral load (VL). Group A: patients with low level VL (n=10) showed a modest increase from <80 to <4 log 10 HIV-1 RNA copies per milliliter plasma during the observation period; Group B: patients with medium level VL (n=12) showed a stronger increase from <80 to >4 log 10 copies per milliliter plasma; and Group C: patients with high level VL (n=11) consistently had a median of >4 log 10 copies per milliliter plasma, during Intervals 1-3, with the exception of one patient who during Interval 2 had 4800 copies per milliliter. Blood lymphocyte subpopulations, proportions of CD4(+) blood lymphocytes coated with IgM, IgG, C3d and/or gp120, in vitro responses to mitogens and pooled allogeneic stimulator cells, as well as numbers of HIV-1 RNA copies per milliliter plasma were measured.

RESULTS

Sequential analysis of VL, IC load on CD4(+) blood lymphocytes and CD4 counts showed that an increasing VL was not associated with CD4 depletion, when the proportion of IC-coated circulating CD4(+) blood lymphocytes remained stable. When, CD4 counts and IC load were analyzed during corresponding intervals of retroviral replication in the three patient groups, a higher VL was associated with lower CD4 counts only when the IC load (IgG or gp120/IgG) on CD4(+) lymphocytes was higher as well.

CONCLUSION

These data suggest that HIV regulates and mediates CD4 depletion in part by the induction of autoreactive ICs against CD4(+) lymphocytes, especially complement-fixing autoreactive IgG and gp120/IgG complexes.

Distinct clonal repertoire of brain CD8+ cells in simian immunodeficiency virus infection

OBJECTIVE

Infection with simian immunodeficiency virus (SIV), like HIV, can lead to central nervous system (CNS) abnormalities. One of the alterations observed in the brain is the accumulation of highly activated CD8 lymphocytes that, while fighting the infection, may cause tissue damage. In order to determine whether these CD8 cells in the brain comprise a distinct clonal population the expression of T-cell receptor (TCR) genes of two SIV-infected monkeys with CNS abnormalities were analyzed, comparing brain to periphery.

METHODS

RNA from magnetically sorted CD8+ cells obtained from the brain, blood, lymph nodes, and spleen was analyzed for the distribution of 24 Vbeta family genes by reverse transcriptase-polymerase chain reaction followed by Southern blot. The CDR3 region of the most enriched family in each brain was sequenced in all the sites for comparison.

RESULTS

The pattern of Vbeta distribution in the brain and the periphery was polyclonal, but an increase in certain Vbeta families was found in the brain, suggesting that regional mechanisms participate in the determination of the local clonal specificities. The sequence of the CDR3 domain of predominant Vbeta families in the brain revealed that approximately one-third of the CD8 cells were not identified in the periphery.

CONCLUSION

CD8 cells in the brain exhibit a distinct clonal repertoire. This distinction may have implications for regional immunity, regulation, or selection of site-specific viral mutants.

Biased T-cell receptor repertoires in patients with chromosome 22q11.2 deletion syndrome (DiGeorge syndrome/velocardiofacial syndrome)

Chromosome 22q11.2 deletion (del22q11.2) syndrome (DiGeorge syndrome/velocardiofacial syndrome) is a common syndrome typically consisting of congenital heart disease, hypoparathyroidism, developmental delay and immunodeficiency. Although a broad range of immunologic defects have been described in these patients, limited information is currently available on the diversity of the T-cell receptor (TCR) variable beta (BV) chain repertoire. The TCRBV repertoires of nine patients with del22q11.2 syndrome were determined by flow cytometry, fragment size analysis of the third complementarity determining region (CDR3 spectratyping) and sequencing of V(D)J regions. The rate of thymic output and the phenotype and function of peripheral T cells were also studied. Expanded TCRBV families were detected by flow cytometry in both CD4+ and CD8+ T cells. A decreased diversity of TCR repertoires was also demonstrated by CDR3 spectratyping, showing altered CDR3 profiles in the majority of TCRBV families investigated. The oligoclonal nature of abnormal peaks detected by CDR3 spectratyping was confirmed by the sequence analysis of the V(D)J regions. Thymic output, evaluated by measuring TCR rearrangement excision circles (TRECs), was significantly decreased in comparison with age-matched controls. Finally, a significant up-regulation in the percentage, but not in the absolute count, of activated CD4+ T cells (CD95+, CCR5+, HLA-DR+), IFN-gamma - and IL-2-expressing T cells was detected. These findings suggest that the diversity of CD4 and CD8 TCRBV repertoires is decreased in patients with del22q11.2 syndrome, possibly as a result of either impaired thymic function and/or increased T-cell activation.

Decreases in plasma TNF-alpha level and IFN-gamma mRNA level in peripheral blood mononuclear cells (PBMC) and an increase in IL-2 mRNA level in PBMC are associated with effective highly active antiretroviral therapy in HIV-infected patients

In this study, we investigated the cytokine profiles of 14 treatment-naive HIV-infected patients on the initiation of highly active antiretroviral therapy (HAART). At baseline, plasma levels of TNF-alpha and its mRNA in peripheral blood mononuclear cells (PBMC) were highest in the most severely immunocompromised patients (<200 CD4+ cells/mm3). After 12 months of HAART, the virus was undetectable in the plasma of all patients (<200 copies/ml), and median CD4 T cell counts had increased (+164 cells/mm3). We also observed a gradual decrease in the number of proviral DNA copies in PBMC and in immune activation, with lower levels of IFN-gamma mRNA in PBMC associated with weaker activation of CD8+ T cells and lower levels of plasma TNF-alpha. IL-2 mRNA levels in PBMC were found to increase in parallel. The decrease in TNF-alpha and IFN-gamma levels and the increase in IL-2 production appear to be correlated with the efficacy of HAART in naive immunocompromised HIV-infected individuals.

Skewed T-cell receptor repertoire, decreased thymic output, and predominance of terminally differentiated T cells in ataxia telangiectasia

Ataxia telangiectasia (A-T), a genetic disorder caused by the homozygous mutation of the ATM gene, frequently associates with variable degrees of cellular and humoral immunodeficiency. However, the immune defects occurring in patients with A-T are still poorly characterized. Here we show that the T-cell receptor (TCR) variable beta (BV)-chain repertoire of 9 A-T patients was restricted by diffuse expansions of some variable genes prevalently occurring within the CD4 subset and clustering to certain TCRBV genes (eg, 5.1, 11, 14, and 23). In addition, the study of the third complementarity-determining region (CDR3) showed, in all patients, significantly altered profiles in most BV genes examined suggesting diffuse oligoclonal expansions. The sequencing of TCR CDR3 regions revealed completely normal V(D)J coding joints and confirmed a reduced diversity of the antigen-receptor repertoire. The B-cell repertoire was similarly restricted and skewed by diffuse oligoclonal expansions with normal V(D)J joints. Thymic output, evaluated by measuring TCR rearrangement excision circles, was extremely low. The majority of peripheral T cells had the phenotype and the function of effector memory cells, indicating that in vivo they are able to respond normally by terminal differentiation to antigenic stimulation. These results indicate that ATM mutation limits the generation of a wide repertoire of normally functioning T and B cells.

Improvement of interleukin 2 production, clonogenic capability and restoration of stromal cell function in human immunodeficiency virus-type-1 patients after highly active antiretroviral therapy

Haematological abnormalities frequently occur in patients infected by human immunodeficiency virus-type 1 (HIV-1). Increasing evidence indicates that bone marrow suppression (BM) results from viral infection of accessory cells, with impaired stromal function and alteration of haematopoietic growth factor network. We have investigated the effects of antiretroviral therapy on cytokine and chemokine production by BM cells and stromal cells in a group of HIV-1-infected subjects before and during treatment. Compared with uninfected controls, an altered cytokine and chemokine production by BM cells was observed before treatment, characterized by decreased interleukin 2 (IL-2) and elevated tumour necrosis factor-alpha, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES (regulated on activation, normal T cell-expressed and secreted) levels, along with a defective BM clonogenic activity. Antiretroviral therapy showed increased BM clonogenic capability, associated with normalization of IL-2 production and chemokine receptors expression on CD34+ cells. Pre-therapy, BM accessory cells were represented by macrophage-like cells, in some cases positive for HIV-1 DNA, suggesting that these cells are the main target of HIV-1 infection. During therapy, the stromal cells became predominantly fibroblastoid-like, as observed in normal controls, and were negative for HIV-1 DNA. Controlling HIV-1 replication may produce amelioration of stem cell activity, and restoration of stromal cell pattern and functions, with increased IL-2 production at BM level.

Immune reconstitution

Immune reconstitution in HIV-infected patients remains a potential mechanism to explain delayed disease progression and increased survival following suppressive therapy. Many discrepancies remain to be studied. Is an immune response to HIV protective? Why are anti-HIV CD4 responses lost so quickly in progressors and how can they be restored? What is the damage to the immune system that occurs early in disease and why can it not be overcome by simply controlling viral replication? Will management of immune reconstitution be used in future adjunct treatment strategies (vaccine or STI)? Because HAART is not the answer to long-term management of HIV throughout the world, the recovery of immune function and it's potential to control viral replication remains a key goal in the long-term management of HIV-infected persons.

Changes in CCR5 and CXCR4 expression and beta-chemokine production in HIV-1-infected patients treated with highly active antiretroviral therapy

The effect of highly active antiretroviral therapy (HAART) on the expression of CCR5 and CXCR4 HIV coreceptors and the production of the beta-chemokines regulated upon activation, normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta has been investigated in 30 HIV-1-infected individuals during 12-36 months of therapy. CCR5 expression was increased in both CD4 + and CD8 + subsets, whereas CXCR4 expression was upregulated only in CD4 + cells. CCR5 levels normalized during 36 months of therapy and positively correlated with the levels of memory, CD95 +, and HLA-DR + T cells. In contrast, the frequency of CXCR4-expressing cells was not significantly modified by HAART, although a downregulation was observed early after starting treatment. CXCR4 levels were significantly associated with the frequencies of naive T cells and negatively correlated with plasma viral load, CD95, and HLA-DR expression. An increased production of both spontaneous and lectin-induced RANTES, MIP-1alpha, and MIP-1beta was found at baseline in HIV-infected individuals. The spontaneous beta-chemokines production was not modified by 12 months of HAART, although a significant reduction was seen during the first months of therapy. A transient decrease of lectin-stimulated RANTES production was also observed, whereas the reduction of lectin-induced MIP-1alpha persisted for up to 12 months of therapy. In contrast, MIP-1beta secreted by phytohemagglutinin antigen-stimulated peripheral blood mononuclear cells progressively increased during HAART. In conclusion, our data indicate a normalization of CCR5 but not CXCR4 expression during suppressive therapy and changes in beta-chemokine production that may play a part in dictating the efficiency of viral infection and consequently the disease course.

T-Cell immune activation in children with vertically transmitted hepatitis C virus infection

Little is known concerning the clinical features, the histological outcome, and the effects on the maturation of immune system of children with vertically-transmitted hepatitis C virus (HCV) infection. Specifically, no data are available on the peripheral distribution of T-cell subsets. The frequency of naive and memory cells, activated T cells, and cytokine-producing T cells was analyzed in nine HCV-infected children born to HCV-positive mothers. In HCV-infected children, the distribution of naive and memory cells was not significantly altered in the CD4 subset whereas within the CD8 subset, an increase of memory and a decrease of naive cells was observed. The frequency of HLA-DR-positive and Fas-positive T cells was increased in HCV-infected children in both CD4 and CD8 subsets. The distribution of Fas-expressing T cells was directly related to that of HLA-DR cells and inversely related to the frequency of naive T cells. In regard with cytokine production we found increased levels of both CD4 and CD8 interferon-gamma (IFN-gamma)-producing cells whereas no difference in the percentage of interleukin-2 (IL-2)-producing T cells was observed. No meaningful correlation was observed between individual T cell subsets and ALT levels or HCV viral load. In conclusion, our results indicate an increased T-cell activation and a shift to a T(H)1 pattern of cytokine production in children with vertically transmitted HCV infection. The cause of this kind of immune response could reside in the persistent antigenic stimulation by chronic HCV infection.